MOUNTAIN HOME, Idaho —

The tip of the rod bobbed like it was pointing to a fish, then convulsed like a willow branch in a gale wind.

Fish on.

With massive weed beds beneath us and the black basalt cliffs of the Snake River Canyon above, safe money would be on a bass causing the commotion on the end of the line. But we were at Crane Falls Lake, so you never know.

A flash of silver popped underwater, and a healthy rainbow trout was soon thrashing at the surface before being landed and released to disappear into the green water.

Crane Falls is a great place to take a float tube, kayak or small boat. It’s the perfect size: large enough for anglers to fish without crowding each other, but small enough that you can cover the whole thing in a day of fishing out of a small boat.

It’s like it was designed for small-boat angling, despite its existence being a happy accident of geography and hydrology.

“Crane Falls is a very odd water body, hydrology-wise,” said Joe Kozfkay, Idaho Fish and Game’s fisheries manager for the Southwest Region. “It was just a dry, natural depression until C.J. Strike Reservoir was formed.

“As C.J. Strike filled, ground water levels rose, creating a fairly deep water body (at Crane Falls), about 30 feet at its deepest point.”

It’s one-third of a trio of waters in the area that includes the Snake River and Cove Arm, a nearby impoundment of the Snake that’s like Crane Falls’ twin.

Idaho Fish and Game recently renovated Crane Falls, and some of the improvements are obvious. Crews rebuilt the boat ramp and the existing restroom.

They also added a new restroom, graded and graveled the roads and partially installed new docks (to be finished within a few weeks) with assistance from Owhyee County, Trout Unlimited and Boise Valley Fly Fishers.

But just as important are improvements you won’t see. Kozfkay explained the lake is fed by ground water, and it has no inlet or outlet. Excess irrigation water from fields above the canyon seep into the ground and through the soils and pick up calcium carbonate before flowing into the lake.

When lake water evaporates, the calcium carbonate stays behind, and in the past, the lake became hyper alkaline, which can stunt fish growth and even become toxic over time.

To prevent it, Fish and Game pumped massive amounts of water out of the lake to let it recharge with water that rebalanced the alkalinity.

“Fast forward to around 2010, and cutbacks caused Fish and Game to reduce water pumping,” Kozfkay said. “Water quality suffered. Bass and bluegill were still numerous, but their growth rates had declined dramatically.

“We estimated age on some 12- to 13-inch largemouth bass, and they were in their teens. This is terribly slow growth.” To make matters worse, the pump and its support structure were old and wearing out, and then rust and ice caused the pump to collapse in 2013.

Fish and Game, with financial assistance from Idaho Power Company, the sport fish restoration program and fishing license dollars, repaired and replaced the pumping facility to improve water quality.

Magnum rainbow trout were stocked earlier this spring, and the bass and bluegill remain. May and early June are among the best months for fishing there, because the lake’s weed beds remain below the surface (they will grow and create mats during the summer).

It’s a fun place to mix trout fishing and warm-water fishing, and anglers also have the option of fishing the nearby Snake River, which has good smallmouth fishing, and Cove Arm Reservoir, which has both species of bass, bluegill, crappie and more.

While it’s best fished from boats, there are limited bank fishing opportunities. The dock and pumping station provide places for bank anglers, and there are several other spots along the shore.

But most of the shoreline is lined with dense vegetation, either reeds or trees, and as the weed beds grow, it further restricts bank angling.

Fishing tips

• Get there early. The Snake River Canyon is often windy, and more likely to be windy midday. Early and late in the day are often the best times to fish and less likely to be windy.

• If there’s a breeze, use it to your advantage. Row, paddle or kick up wind, and then drift back trailing your bait of fly. It’s an effective way to fish. There’s a road on both sides of the lake if it’s too windy to paddle back. It’s a fairly short walk back to your vehicle.

• Bluegill provide a lot of fast action, but they tend to be congregated in certain areas. Spend some time searching for them.

• Trolling works well for trout, which tend to be dispersed throughout the lake. The area in front of the pump station is deep and mostly weed-free. Trolling flies works, too.

• Don’t ignore those weed beds. They will harbor a lot of bass, and you can use topwater lures and flies to effectively fish them.

• Use tackle that will attract different species of fish. A big trolling rig probably won’t catch bass or bluegill, but a small grub will catch trout.